Plasma display panel and method for manufacturing the same

ABSTRACT

A plasma display (PDP) manufacturing method and display panel includes a display electrode forming step of forming a plurality of pairs of display electrodes in parallel lines on a main surface of a first plate, and a plate sealing step of aligning the main surface of the first plate with a main surface of a second plate, and sealing the first and second plates together. The display electrodes are formed by coating the main surface of the first plate with display electrode material, and performing laser ablation on parts of the display electrode material, while the remaining parts of the display electrode material form the display electrodes.

TECHNICAL FIELD

This invention relates to a plasma display panel, and a manufacturingmethod for the same.

BACKGROUND ART

Large screen display devices with high picture quality, such as thatproduced by high definition television (HDTV), have recently become thefocus of much expectation. As a result, research and development ofdisplay devices such as cathode ray tubes (CRTs), liquid crystaldisplays (LCDs), and plasma display panels (PDPs) is taking place. Thesevarious types of display devices each have the followingcharacteristics.

CRTs have excellent resolution and picture quality, and are widely usedin conventional televisions and the like. The large increases in depthand weight required to produce a large screen CRT, however, areproblematic, and solving this difficulty is crucial for the developmentof such CRTs. Due to this problem, it is believed to be difficult toproduce a CRT with a large screen of more than 40 inches.

LCDs, on the other hand, use less electricity than CRTs, and areextremely light and slim. Nowadays, LCDs are being increasingly used ascomputer monitors. However, the structure of a typical LCD, which uses athin film transistor (TFT) screen or similar, is extremely intricate,and this means that manufacture of such a device requires a plurality ofcomplicated processes. As a result, manufacturing yield decreases asscreen size is increased. This means that it is currently considereddifficult to manufacture an LCD with a screen of more than 20 inches.

In contrast to CRTs and LCDs, PDPs have the advantage of being able torealize a lightweight display with a large screen, and in additionemploy a driving method in which the PDP itself emits light to produce ascreen display. As a result, in the current search for the nextgeneration of displays, research and development of large screen PDPs isbeing pursued particularly aggressively, and products with screens ofmore than 50 inches are being developed.

In a PDP, a glass substrate, on which a plurality of pairs of displayelectrodes and a plurality of barrier ribs are arranged in a stripeformation, is placed in opposition to another glass substrate. Phosphorsin each of the three colors red, green and blue are applied to thespaces between the barrier ribs. The two glass substrates are thensealed together so as to be airtight, and a discharge gas enclosed inthe discharge space between the barrier ribs and the two glasssubstrates. Discharge is produced by ultraviolet light generated by thedischarge gas, thereby causing the phosphors to emit light. PDPs such asthis one can be divided into two types, direct current (DC) andalternating current (AC), according to the driving method used. AC PDPsare thought to be more suitable for producing a large screen device, andthus are the most common type of PDP.

However, current specifications for HDTV include a 1920×1080 pixelarray, and a dot pitch of 0.16 mm×0.48 mm for 42-inch class screens.Consequently, the area occupied by one cell is as little as 0.077 mm²,which is seven to eight times smaller than the size specified by theNTSC (National Television System Committee) standard for televisions inthe same 42-inch class, and the number of scanning lines is almost threetimes as great as that specified in the NTSC standard. For thesereasons, the manufacturing processes required to produce PDPs for HDTVuse are of higher precision than those required to produce a televisioncomplying with the NTSC standard.

Consequently, the plurality of pairs of display electrodes in a PDP haveto be set at intervals smaller than those in televisions compliant withthe NTSC standard.

However, this creates certain problems when manufacturing the PDP. Theplurality of pairs of electrodes are generally manufactured using amethod disclosed in Japanese Laid-Open Patent 9-35628. The actualprocedure for manufacturing electrodes using such a method is asfollows. First, a transparent conductive film formed from indium tinoxide (ITO) or tin oxide (SnO₂), and a metal conductive film formed fromthree layers of chromium, copper and chromium (Cr—Cu—Cr) aresuccessively formed on the surface of a front glass substrate usingsputtering or a similar method. Following this, photolithography is usedto process the conductive film so that the electrodes have a uniformshape. Photolithography is performed by repeating processes in which aphotoresist is applied, and patterning and etching performed.Consequently, a large number of process steps are used, and theoperation tends to take a long time. Furthermore, unwanted erosioncaused by the etching solution, and slipping of the mask used forpatterning are more likely to occur as the processes are repeated,making it difficult to preserve the same level of precision throughoutthe entire procedure. These problems are a particular obstacle whenmanufacturing the intricately-formed plurality of pairs of displayelectrodes used for HDTV.

There is still a great deal of room for improvement in current PDPmanufacturing methods with regard to the technical problem of how tomanufacture a plurality of pairs of display electrodes in a way that isfaster and more precise than conventional methods.

DISCLOSURE OF THE INVENTION

The present invention was developed with the aim of solving the aboveproblem. The object of the invention is to provide a PDP manufacturingmethod that incorporates laser ablation processing into the process usedto manufacture the plurality of display electrodes and the like, therebyrationalizing the manufacturing process by shortening the time required,and manufacturing a PDP with a high yield.

The above object may be realized by a plasma display panel manufacturingmethod including a display electrode forming step of forming a pluralityof pairs of display electrodes in parallel lines on a main surface of afirst plate, and a plate sealing step of aligning the main surface ofthe first plate with a main surface of a second plate, and sealing thefirst and second plates together. Here, the plurality of pairs ofdisplay electrodes are formed in the display electrode forming step bycoating the main surface of the first plate with display electrodematerial, and performing laser ablation on parts of the displayelectrode material. Remaining parts of the display electrode materialform the display electrodes.

To be more specific, in the display electrode forming step, the displayelectrode material may contain transparent electrode material and metalelectrode material, and the plurality of pairs of display electrodes maybe formed using the following method. First, the main surface of thefirst plate is coated with the transparent electrode material, and laserablation performed on the transparent electrode material to formtransparent electrode parts. Then, at least surfaces of the transparentelectrode parts are coated with the metal electrode material to formmetal electrode parts that are in electrical contact with thetransparent electrode parts.

Furthermore, in the display electrode forming step, the plurality ofpairs of display electrodes may be formed in the following way. Laserablation is performed on the transparent electrode material to formtransparent electrode parts and alignment marks. Then, at least surfacesof the transparent electrode parts are coated with metal electrodematerial to form metal electrode parts, the alignment marks being usedto align the metal electrode material with the transparent electrodeparts.

If a plurality of pairs of display electrodes are manufactured in thisway, laser processing can be performed simply by performing a laserablation process, and then washing and drying processes. Therefore, theplurality of pairs of display electrodes can be formed more quickly andusing a fraction of the number of processes required by a conventionalphotolithography method or the like. This reduces the generation ofenvironmentally harmful waste solutions and the like, so that the use ofthe laser ablation process is likely to resolve various environmentalproblems. The laser ablation process can also be used to manufacturealignment marks, in addition to manufacturing the plurality of pairs ofdisplay electrodes.

Furthermore, a plasma display panel manufacturing method including adisplay electrode forming step and a plate sealing step may be used.Here, in the display electrode forming step, a plurality of pairs ofdisplay electrodes are formed in parallel lines on a main surface of afirst plate. Then, in the plate sealing step, the main surface of thefirst plate is aligned with a main surface of a second plate on which aplurality of address electrodes have been arranged in parallel lines andthe first and second plates sealed together, may be used. The plates arealigned so that the plurality of pairs of display electrodes intersectwith the address electrodes. Here, the plurality of pairs of displayelectrodes may be formed in the display electrode forming step in thefollowing way. The main surface of the first plate is coated withdisplay electrode material, and laser ablation performed to vaporizeparts of the display electrode material by applying a first laser beamand a second laser beam in parallel to the display electrode material.The remaining parts of the display electrode material form the displayelectrodes.

In addition, in the display electrode forming step, the plurality ofpairs of display electrodes may be formed by performing laser ablationon parts of the display electrode material coating the main surface ofthe first plate by applying (1) a first laser beam of a first strengthand (2) a second laser beam of a second strength different from thefirst strength.

By using laser beams of a first strength (or a first spot shape), and asecond strength (or a second spot shape) to form the plurality of pairsof display electrodes, a plurality of pairs of display electrodes havinggaps of different widths in various places can be formed, and theresistance value correction and precision repairs can be performed onthe plurality of pairs of display electrodes. When this is combined withthe above effects, the laser ablation process can be furtherstreamlined.

Furthermore, a plasma display panel may be formed by aligning a mainsurface of a first plate, on which a plurality of pairs of displayelectrodes have been formed in parallel lines, with a main surface of asecond plate, and sealing the first and second plates together. Here,alignment marks for performing plate alignment may be formed using laserablation on at least one of the main surface of the first plate and themain surface of the second plate.

In addition, a plasma display panel may be formed by aligning a mainsurface of a first plate with a main surface of a second plate, andsealing the first and second plates together, a plurality of pairs ofdisplay electrodes having been formed in parallel lines on the mainsurface of the first plate. Each pair of display electrodes is formedfrom a transparent electrode part and a metal electrode part that are inelectrical contact. Here, alignment marks for performing alignment ofthe transparent electrode parts and the metal electrode parts may beformed on the main surface of the first plate, the transparent and metalelectrode parts having been formed by laser ablation.

Here, alignment marks may be provided on the main surface of the firstplate for plate alignment, and for alignment of the transparentelectrode parts with the metal alignment parts. Consequently, the mainsurfaces of the first and second plates and the transparent and metalelectrodes can be precisely assembled, and a plasma display panel thatmakes full use of current technology can be produced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagonal cross-section of part of a surface discharge ACPDP in a first embodiment;

FIG. 2 is an aerial view of a pattern formed by a plurality of pairs ofdisplay electrodes in the first embodiment;

FIG. 3 is a partial cross-section of a front glass substrate 21, showinga manufacturing process for a pair of display electrodes in the firstembodiment;

FIG. 3A shows a situation in which a transparent conductive film 50covers the surface of the front glass substrate 21;

FIG. 3B shows a situation in which the transparent conductive film 50 iseliminated at either edge of the front glass substrate 21 in a directionx, in order to create electrode extension forming areas 210;

FIG. 3C shows a situation in which transparent electrode parts 221 and231 are formed using laser ablation;

FIG. 3D shows a situation in which a metal conductive film 60 isapplied;

FIG. 3E shows a situation in which metal electrode parts 222 and 232 areformed using etching (a wet photolithography process);

FIG. 4 shows external views of various parts of a gantry-type laserprocessing device 100;

FIG. 4A is an external diagonal view of the gantry-type laser processingdevice 100;

FIG. 4B is a frontal enlargement of a laser torch 102;

FIG. 4C is a frontal view showing the shape of apertures 1031 and 1041in the laser torch 102;

FIG. 5 shows a laser ablation process relating to the manufacture oftransparent electrode parts 221 and 231 in the first embodiment;

FIG. 5A is a diagonal view of part of the front glass substrate 21showing a procedure for forming the transparent electrode parts 221 and231 using a first laser beam and a second laser beam;

FIG. 5B is a front view of part of the front glass substrate 21 showinga process for forming gaps between a pair of transparent electrode parts221 and 231;

FIG. 6 shows settings for laser work relating to a laser ablationprocess performed by the laser processing device 100 in the firstembodiment;

FIG. 6A is a finished view of the transparent electrode parts 221 and231 finished by the laser ablation process;

FIG. 6B shows a sequence of laser work relating to the laser ablationprocess;

FIG. 7 is a partial cross-section of the front glass substrate 21showing a manufacturing process for a plurality of pairs of displayelectrodes in a second embodiment;

FIG. 7A shows a situation in which a metal conductive film 60 is appliedto the surface of the front glass substrate 21;

FIG. 7B shows a situation in which unnecessary parts of the metalconductive film 60 are eliminated by laser ablation;

FIG. 7C shows a situation in which the metal conductive film 60 isannealed by laser ablation;

FIG. 8 shows the laser ablation process performed on the metal electrodeparts 232 in the second embodiment;

FIG. 8A is a partial cross-section of the front glass substrate 21showing a metal electrode part 232 before annealing has been performed;

FIG. 8B is a partial cross-section of the front glass substrate 21showing the metal electrode part 232 after annealing has been performed;

FIG. 9 is a front view of the front glass substrate 21, showing a laserablation process in a first variation of the embodiments (manufacture ofthe transparent electrodes 221 and 231 and adjustment of resistancevalues thereof);

FIG. 10 is a front view of the front glass substrate 21 showing a laserablation process in a second variation of the embodiments (manufactureof the transparent electrodes 221 and 231 and detailed repairs performedthereon);

FIG. 11 is a front view of the front glass substrate 21 showing a laserablation process in a third variation of the embodiments (manufacture ofthe transparent electrodes 221 and 231 and adjustment of resistancevalues thereof, when a mask 300 has been affixed to the front glasssubstrate 21);

FIG. 12 is a cross-section of the front glass substrate 21 showingshapes of edges 80 a to 82 a, and 80 b to 82 b, of the transparentelectrode parts 221 and 231 in the first variation of the embodiments;

FIG. 12A is a partial cross-section of the front glass substrate 21showing edges 80 a and 80 b in cross-section;

FIG. 12B is a partial cross-section of the front glass substrate 21showing edges 81 a and 81 b in cross-section;

FIG. 12C is a partial cross-section of the front glass substrate 21showing edges 82 a and 82 b in cross-section;

FIG. 13 is a partial cross-section of the front glass substrate 21showing the manufacturing process for the edges 82 a and 82 b;

FIG. 13A is a partial cross-section of the front glass substrate 21showing a situation in which a photoresist 70 has been applied;

FIG. 13B is a partial cross-section of the front glass substrate 21showing a situation in which the photoresist 70 has been exposed and analkaline solution applied; and

FIG. 13C is a partial cross-section of the front glass substrate 21showing the formed edges 82 a and 82 b that have been formed, incross-section.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

FIG. 1 is a diagonal cross-section of part of a surface dischargealternating current (AC) PDP in a first embodiment. In the drawing, a zdirection corresponds to the depth of the PDP, and an xy planecorresponds to a plane parallel with the PDP surface. As shown in thedrawing, the structure of the PDP can be broadly divided into a frontplate 20 and a back plate 26. In this and all relevant subsequentdrawings (FIGS. 1 to 10), the x, y, and z directions are identical.

A front glass substrate 21 forming the base of the front plate 20 iscomposed from soda lime glass. A plurality of pairs of displayelectrodes 22 and 23 (each pair is formed from an X electrode 22 and a Yelectrode 23) are arranged on the surface of the front glass substrate21 facing the back plate 26, extending in the x direction and being afixed interval apart in the y direction. The X electrodes 22 are used asscan electrodes when addressing is performed, and this feature is commonto all the embodiments of this invention. An overall view of theplurality of pairs of display electrodes 22 and 23 is describedhereafter.

A dielectric layer 24 formed from a lead oxide composite is coated overthe surface of a front glass substrate 21 on which the plurality ofpairs of display electrodes 22 and 23 have been arranged, so that theplurality of pairs of display electrodes 22 and 23 are embedded in thedielectric layer 24. A protective layer 25 formed from magnesium oxide(MgO) is then coated over the surface of the dielectric layer 24.

A back glass substrate 27 forming the base of the back plate 26 ismanufactured in a similar way to the front glass substrate 20. Aplurality of address electrodes 28 are arranged at fixed intervals inthe x direction on the surface of the back glass substrate 27 facing thefront plate 21, extending in the y direction, thereby forming a gridpattern with the plurality of pairs of display electrodes 22 and 23 onthe front glass substrate 20. A dielectric film 29 formed from the samesubstance as the dielectric layer 24 is formed on the surface of theback glass substrate 27, so as to surround the address electrodes 28.Then a plurality of barrier ribs 30 of uniform width and height areformed along the y direction on the surface of the dielectric film 29,in the gaps between neighboring address electrodes 28. Red, blue andgreen phosphors 31, 32, and 33 are applied in turn to the sides of thebarrier ribs 30 and the surface of the dielectric film 29.

The front plate 20 and the back plate 26 are fixed together usingsealing glass. Then, a discharge gas including an inert gas is enclosedin the spaces formed between the plurality of barrier ribs 30. Each ofthese spaces is a long narrow display space 38, extending in the ydirection. Areas within each discharge space 38 at which a pair ofdisplay electrodes 22 and 23 intersect with an address electrode 28 arecells (explained later in the description) for screen display. Cells arearranged in rows and columns in the x and y directions respectively,forming a matrix. As a result, the PDP can form a matrix display byswitching individual cells on and off at the appropriate times.

FIG. 2 is an aerial view of the display electrode pattern of the PDP,looking down in the z direction. In order to simplify the drawing, thebarrier ribs 30 are not shown. In the drawing, areas divided by brokenlines correspond to cells 11, 12, 13, and 14.

As shown in FIG. 2, each of the plurality of pairs of display electrodes22 and 23 in the PDP is formed from transparent electrode parts 221 and231, and metal electrode parts 222 and 232. The metal electrode parts222 and 232 are arranged, so as to be electrically connected, on theoutermost parts of each of transparent electrode parts 221 and 231. Thetransparent electrode parts 221 and 231 have protrusions 220 and 230respectively, protrusions 220 and 230 formed facing each other at eachcell pitch (the pitch between neighboring address electrodes 28) in thegaps 36 between pairs of display electrodes 22 and 23.

The size of each part of the display electrodes 22 and 23 is as follows.A gap 35 between facing protrusions 220 and 230 is 80 μm, a maximum gap36 between a pair of address electrodes 22 and 23 is 520 μm, andprotrusions 220 and 230 are rectangular, being 150 μm in the x directionand 220 μm in the y direction. Furthermore, the width of the transparentelectrode parts 221 and 231, excluding the protrusions 220 and 230, is150 μm, and a gap 37 between neighboring pairs of display electrodes 22and 23 is 260 μm. Here, a characteristic of the first embodiment is thatthe transparent electrode parts 221 and 231 described above aremanufactured using the laser ablation process described later in thisdescription.

Furthermore, the width of each of the metal electrode parts 222 and 232is 50 μm, and the cell pitch is 360 μm.

Note that in FIG. 2, the protrusions 220 and 230 have been madeproportionally larger, and the maximum gap 36 between the pairs ofdisplay electrodes 22 and 23 proportionally narrower, than is actuallythe case, in order to make the characteristic shape of the displayelectrodes 22 and 23 having the protrusions 220 and 230 clearer.

The reason for setting the transparent electrode parts 221 and 231 inthis kind of pattern is to restrict the surface discharge startingvoltage and therefore obtain surface discharge of a sufficient scale.

In other words, the PDP having the above structure generates two typesof discharge by applying an appropriate power supply to the electrodes22, 23, and 28 when the PDP is driven.

One type of discharge is an address discharge for controlling theswitching of cells 11, 12 and so on between on and off. This dischargeoccurs when power is supplied to an X electrode 22 (a scan electrode)and an address electrodes 28.

The other type of discharge is sustain discharge (surface discharge)that directly contributes to the screen display performed by the PDP.This discharge occurs when a pulse voltage is applied to a pair ofdisplay electrodes 22 and 23.

Surface discharge starts when a pulse voltage is supplied to a pluralityof pairs of display electrodes 22 and 23. Here, surface discharge startsin the gaps 35 between the protrusions 220 and 230, but since the gaps35 between the protrusions 220 and 230 are each about 80 μm wide andthus narrower than the maximum gap 36 between each pair of displayelectrodes 22 and 23 (about 520 μm), the discharge starting voltage canbe restricted to a low level.

Therefore, when the surface discharge starts, the scale of dischargegradually increases, thereby improving luminance, and restricting thelevel of the discharge voltage, so that the PDP has sufficient luminousefficiency.

To be more precise, if a 185V voltage is applied to the pairs of displayelectrodes 22 and 23 when surface discharge is generated, variations ofabout ±5V in the level of the actual voltage applied to the pairs ofdisplay electrodes 22 and 23 are evident in a conventional PDP. Incontrast, the transparent electrode parts 221 and 231 in a PDPmanufactured according to the first embodiment can be manufactured moreprecisely than in a conventional PDP by using laser ablation. As aresult, voltage variation can be limited to ±2V. Thus, the PDP of thepresent invention can be given superior display characteristics, inwhich flicker has been reduced to less than that in a conventional PDP.

The main characteristic of the invention is a PDP manufacturing method.The following is a description of a PDP manufacturing method in thefirst embodiment of the invention.

PDP Manufacturing Method

i. Manufacture of the Front Plate 20

Display electrodes 22 and 23 are formed on a surface of a front glasssubstrate 21, the front glass substrate 21 being a soda lime glass platewith a thickness of about 2.66 mm. Here, a characteristic of theinvention is that the plurality of pairs of display electrodes 22 and 23are formed using laser ablation. The procedure for forming the pairs ofdisplay electrodes 22 and 23 is explained with reference to the partialcross-sections of the front glass substrate 21 shown in FIGS. 3A to 3E,the block diagrams of the laser processing device 100 shown in FIGS. 4Ato 4C, the laser ablation process shown in FIGS. 5A and 5B, thecompleted view of the transparent electrode parts 221 and 231 shown inFIGS. 6A and 6B, drawings showing the laser work operation performedduring the laser ablation process, and the like.

The pairs of display electrodes 22 and 23 in the first embodiment areformed from the transparent electrode parts 221 and 231, and the metalelectrode parts 222 and 232 mentioned previously. First, the transparentelectrode parts 221 and 231 are formed by coating the entire surface ofthe front glass substrate 21 with a transparent conductive film ofSnO₂—Sb₂O₃ (a composite in which hydrated tin oxide (SnO₂) and antimonyoxide (Sb₂O₃) are mixed so that the atomic ratio of tin to antimony is98:2) using chemical vapor deposition (CVD), forming a transparentconductive film 50 having a thickness of approximately 0.2 μm. CVD isperformed by transforming the materials required to create thetransparent conductive film 50 into a gas, and forming the transparentconductive film 50 by circulating the gas over the surface of the frontglass substrate 21, the front glass substrate 21 having been heated to ahigh temperature of about 550° C. FIG. 3A shows a situation in which thetransparent conductive film 50 has been formed.

Next, electrode extension forming areas 210 corresponding to a strip ateach side of the front glass substrate in the x direction are secured inthe transparent conductive film 50 (see FIGS. 3B and 6). Although notshown in the drawing, the electrode extension is an electrode part thatextends in a straight line from the metal electrode parts 222 and 232 inorder to connect the display electrodes 22 and 23 to a drive circuit(not shown in the drawing). Next, the transparent electrode film 50 ispatterned to form the transparent electrodes 221 and 231 (see FIG. 3C).An illustration of the electrode extension forming areas 210 can befound in FIG. 6.

This procedure is implemented using a laser processing device 100, adiagonal view of which is shown in FIG. 4A. The laser processing device100 is of what is known as a gantry type, and is a widely known laserprocessing device having a single-axle table 103 (capable of movingfreely back and forth in the x direction), and a single-axle laser torch102 (capable of moving freely back and forth in the y direction). Thelaser torch 102 is connected to a laser torch guide 101, which isarranged so as to straddle the table 103 in the y direction, and movesback and forth in the y direction under the guidance of the laser torchguide 101. The laser torch 102 and the table 103 are precision-driven bya stepping motor (not shown). By moving the laser torch 102 and thetable 103 respectively in the x and y directions in relation to aworkpiece placed on the table 103, two-dimensional laser ablation ofmicro order precision can be achieved.

The laser torch 102 is constructed as shown in FIG. 4B, so that a firstlaser head 1030 and a second laser head 1040 are fixed to a main body1020 by fixing jigs 1021 and fastening bolts 1022. The first and secondlaser heads 1030 and 1040 emit a YAG (yttrium-aluminum-garnet) laserbeam with a wavelength of 1.06 μm, and are connected respectively toends of silica fiber-optic cables 1032 and 1042, the silica fiber-opticcables 1032 and 1042 extending from a laser oscillator (not shown). Thefirst and second laser heads 1030 and 1040 are housed inside an opticalunit that concentrates laser beams. Apertures 1031 and 1041 andobjective lens units 1050 and 1060 are fitted to the respective ends ofthe first and second laser heads 1030 and 1040. Laser ablation of auniform pattern can be performed by having the first and second laserheads 1030 and 1040 emit pulse lasers to form a plurality of connectedoverlapping laser spots.

Here, the aperture 1031 is formed so that it corresponds in size withthe sum of the gap 35 between facing protrusions 220 and 230 and themaximum gap 36 between a pair of display electrodes 23 and 23, and theaperture 1041 is formed so that it corresponds to the size of the gap 37between two pairs of neighboring display electrodes 22 and 23. Theaperture 1031 forms a laser spot pattern on the surface of the frontglass substrate 21 that has been fixed onto the table 103, using acombination of objective lens units 1050 and 1060. Here, the laser spotpattern is formed by combining rectangles of 520 μm in the y directionand 210 μm in the x direction with rectangles of 80 μm in the ydirection and 150 μm in the x direction. The aperture 1041 has a slitfor forming laser spots on the surface of the front glass substrate 21that has been fixed onto the table 103, using a combination of theobjective lens units 1050 and 1060. Here, the laser spots are eachrectangles of 260 μm in the y direction and 360 μm in the x direction. Aprotrusion 1031 a of aperture 1031 is provided to form the protrusions220 and 230 of the transparent electrode parts 221 and 231. If first andsecond laser beams are output from first and second laser heads 1030 and1040, the corresponding laser spot patterns are applied to the surfaceof the front glass substrate 21 on the table 103, via the apertures 1031and 1041 and the objective lens units 1050 and 1060. Note that the sizeof laser spots formed on the surface of the front glass substrate 21 canbe appropriately adjusted by altering the position of the first andsecond laser heads 1030 and 1040 in relation to the laser torch 102. Thefront glass substrate 21 is fixed onto the table 103 of the gantry-typelaser processing device 100 constructed as above, paying attention tothe orientation of the front glass substrate 21. In other words, thefront glass substrate 21 is fixed horizontally onto the table 103 usinga method well known in the art such as a vacuum chuck method, so thatthe x and y directions of the front glass substrate 21 correspond to thex and y directions of the laser processing device 100.

Next, laser beam output settings are performed. Both the first andsecond laser heads 1030 and 1040 have laser beams with a pulse laseroutput of 100 nsec/pulse, and a strength set at 1.5 mJ/pulse.

Following setting of the laser beam output, laser ablation settings areset from a fixed setting input menu for the laser processing device 100,in accordance with the pattern shown in FIG. 6A. Here, the basic laserablation processing sequence involves performing laser ablation on thetransparent conductive film 50 covering the entire surface of the frontglass substrate 21, and forming transparent electrode parts 221 and 231,remaining parts of the transparent conductive film 50, and cross-shapedalignment marks. Once the laser ablation setting has been performed, anda work starting instruction input, laser ablation starts automatically.

Laser ablation may, for example, start by ensuring that the electrodeextension forming areas 210 are formed at the left and right edges ofthe front glass substrate (in the x direction). This is performed byusing the second laser beam from the second laser unit 1040 inisolation.

In other words, the positional relationship between the table 103 andthe laser torch 102 is adjusted, so that one corner of the front glasssubstrate 21 (in FIG. 6A, the bottom left corner of the front glasssubstrate 21) is positioned directly beneath the second laser head 1040.Then laser ablation is performed on parts of the transparent conductivefilm 50 covering the front glass substrate 21 by outputting the secondlaser beam while moving the laser torch 102 in the y direction, with thetable 103 still in a fixed position. This causes a groove with a widthof 360 μm to be formed on the surface of the front glass substrate 21 inthe y direction by vaporizing the transparent conductive film 50.

Once one laser ablation stroke is completed (one stroke is one passacross the front glass substrate 21 in the y direction), the table 103is moved slightly just 360 μm, that is the x width of the laser spot ofthe second laser beam, in the x direction. Then laser ablation isperformed as before by moving the laser torch 102 in the y directionfrom this position. Laser ablation is performed using this forward andbackward operation for two x 56 strokes (for the two side areas of thefront glass substrate 21 in the x direction), forming an electrodeextension forming area 210 with a width of about 20 mm at each end ofthe front glass substrate 21 (in the x direction). This completes thelaser ablation process shown in FIG. 3B.

Next, the remaining parts 211 of the transparent conductive film 50,alignment marks 212 and the like are formed using laser ablation. FIG.6B is a drawing showing a visualization of the laser ablation processperformed at this time. In the drawing, the positional relationship ofthe table 103 and the laser torch 102 is adjusted, so that one corner(in FIG. 6B the bottom left corner) of the front glass substrate 21 ispositioned directly beneath the second laser head 1040. Then, crossesare formed at fixed positions on the transparent conductive film 50 bylaser ablation, while moving the table 103 slightly in the x and ydirections. This forms reverse alignment marks 212. Alignment marks 212are formed, for example, by combining laser spots produced by theaperture 1041 to form a cross shape 980 μm in length in the y direction(i.e. four laser spot diameters in the y direction), and 1080 μm inlength in the x direction (i.e. three laser spot diameters in the xdirection). Alignment marks 212 are formed to be used for positionalalignment of the transparent electrode parts 221 and 231 with the metalelectrode parts 222 and 232 and for positional alignment when the frontglass substrate 21 and the back glass substrate 27 are fixed together.The fixed positions of the alignment marks 212 are, for example, asshown in FIG. 6A, with three alignment marks 212 being formed 5 mm fromthe bottom of the front glass substrate 21 in the y direction, atintervals on a straight line extending lengthwise along the front glasssubstrate 21.

Once these alignment marks 212 have been formed, the table 103 is movedso that one edge of the front glass substrate 21 in the x direction (inFIG. 6B the right edge) is directly beneath the second laser head 1040.Then, the laser torch 102 is moved 5 mm in the y direction, and thefront glass substrate 21 moved back in the x direction while the secondlaser beam is applied to the transparent conductive film 50. This laserablation stroke (one pass of the laser beam across the front glasssubstrate 21 in the x direction: see FIG. 6B), forms a strip with awidth of about 260 μm by vaporizing the transparent conductive film 50,with a remaining part 211 of the transparent conductive film 50 that is10 mm wide being left at each side of the front glass substrate 21 inthe x direction.

Once a remaining part 211 has been formed, the front glass substrate 21is moved so that an edge of the front glass substrate 21 in the xdirection (in FIG. 6B the left edge) is beneath the laser torch 102.Then, the laser torch 102 is moved 1080 pm in the y direction, relativeto the table 103, and the first and second laser heads 1030 and 1040 areplaced in an operation-ready state. (Here, the maximum gap between apair of display electrodes 22 and 23 (520 μm)+a gap between two pairs ofneighboring electrodes 22 and 23 (260 μm)+the width of a pair of displayelectrodes 22 and 23 excluding the protrusions 220 and 230 (150μm×2)=1080 μm (see FIG. 2 for more details)). Following this, the table103 is moved in the x direction while the first and second laser beamsare applied in parallel to the transparent conductive film 50 in the ydirection, thereby forming a gap 36 between a pair of display electrodes22 and 23, and a gap 37 between neighboring pairs of display electrodes22 and 23, in parallel on the front glass substrate 21. The transparentelectrode parts 221 and 231 for one pair of display electrodes 22 and 23are formed by this laser ablation process.

Here, FIG. 5A is a diagonal view of part of the front glass substrate 21showing a situation in which a pair of display electrodes 22 and 23 arebeing formed by laser ablation. In this laser ablation, a laser beam isemitted as an intermittent pulse laser, as is the case for laserablation performed by the first laser beam shown in FIG. 5B. Thetransparent electrode parts 221 and 231 are formed by connecting laserspots emitted by this pulse laser.

Note that electrode gaps 35 to 37 may be more accurately formed byperforming laser scanning so that neighboring laser spot overlapslightly in the x direction. However, in this case, an arrangement thattakes account of the overlapping laser spot portions by, for example,setting the shapes of the apertures 1031 and 1041 lengthwise in the xdirection, is required.

Furthermore, an edge of the front glass substrate in the x directionneed not be positioned directly beneath the first and second laser heads1030 and 1040 when moving the laser torch 102 in the y direction.Instead, the laser torch 102 may be moved so that it is positioneddirectly over an end of the transparent electrode parts 221 and 231 inthe x direction.

The number of laser torches used need not be limited to one, and aplurality of laser torches may be used, so that each laser head isattached to a different laser torch.

In this laser ablation process used to form the transparent electrodeparts 221 and 231, processes for forming the transparent electrode parts221 and 231 for a pair of display electrodes 22 and 23 using laserablation, and for moving the laser torch 102 slightly about 1080 pm inthe y direction are repeated in accordance with the laser ablationprocessing order shown in FIG. 6B. A plurality of transparent electrodeparts 221 and 231 for pairs of display electrodes 22 and 23 are formedon the front glass substrate 21 (in the case of a 42-inch XGA (extendedgraphics array) panel a total of 768 pairs are formed) by performing alaser ablation processing sequence in which laser ablation in the xdirection and movement of the laser torch 102 in the y direction arecombined in a zigzag processing sequence.

Once all of the transparent electrodes 221 and 231 have been formed(FIG. 3C), driving of the first laser head 1030 is temporarilysuspended. Then, the remaining part 211 at the top edge of thetransparent conductive film 50 is formed as was previously explained bydriving only the second laser head 1040. Once the remaining part 211 hasbeen formed, a plurality of alignment marks 212 are formed using thepreviously described operation. With this, the laser ablation processfor one front glass substrate 21 is completed.

A wet photolithography method conventionally performed in order tomanufacture the plurality of pairs of display electrodes 22 and 23requires approximately eleven separate steps. In contrast, the laserablation process disclosed in the first embodiment can be completedusing just three steps: a laser process step, and washing and dryingprocess steps for which laser ablation is not required. Furthermore, thelaser ablation process can be performed in just 10 minutes or so. Thisimproves the yield of the PDP manufacturing process, and is also aneffective cost-cutting measure.

The transparent electrode parts 221 and 231 can be manufactured withgreater precision when using this laser ablation process than whenanother manufacturing method is used. If the transparent electrode parts221 and 231 are strips extending in the x direction with a width ofabout 50 μm, errors in size of about ±5.0 μm will be generated when aphotolithography method is used, but errors can be restricted to ±3.0 μmwhen the method disclosed in the first embodiment is used.

After the above laser ablation process has been performed, the frontglass substrate 21 is removed from the table 103, and a metal conductivefilm 60 having a thickness of 0.1 μm is formed using a sputtering methodby coating the surface of the front glass substrate 21, on which thetransparent electrode parts 221 and 231 have been formed, with alaminated Cr—Cu—Cr film (FIG. 3D).

Next, a wet photolithography process is used on the metal conductivefilm 60, thereby forming metal electrode parts 222 and 232 (FIG. 3E) andelectrode extensions (not shown). The wet photolithography process isconventionally performed using the following steps (a) to (k): (a)washing the metal conductive film 60→(b) applying a photoresist to themetal conductive film 60→(c) drying→(d) applying a mask in the shape ofthe metal electrode parts 222 and 232 and exposing the photoresist→(e)developing→(f) rinsing→(g) washing and drying→(h) hardening thephotoresist remaining on top of the metal conductive film 60→(i)etching→(j) peeling off the photoresist→(k) washing and drying.

Note that the mask is applied in step (d), so as to be aligned on themetal conductive film 60 using the alignment marks 212. This ensuresthat accurate developing can be performed.

Furthermore, the metal electrode parts 222 and 232 are here formed alongthe outer edges of each of the transparent electrode parts 221 and 231in each pair of display electrodes 22 and 23, in strips with a width ofabout 50 μm.

Next, a lead glass paste is applied to the entire surface of the frontglass substrate 21 over the tops of plurality of the display electrodes22 and 23 at a thickness of about 20 to 30 μm, and fired to form thedielectric layer 24.

Following this, a protective layer 25 of MgO with a thickness of about 1μm is formed on the surface of the dielectric layer 24 using vapordeposition or CVD.

This completes manufacture of the front plate 20.

ii. Manufacture of the Back Plate 26

A conductive material with silver as a main component is applied, usingscreen printing, at fixed intervals in a stripe pattern to the surfaceof a back glass substrate 27, the latter being a soda lime glass platewith a thickness of 2 mm. This forms a plurality of address electrodes28, having a thickness of 5 μm. Here, the interval between neighboringaddress electrodes 28 is set at 360 μm.

Next, a lead glass paste is applied at a thickness of between 20 μm to30 μm to the entire surface of the back glass substrate 26 on which theaddress electrodes 28 have been formed, and then fired, thereby formingthe dielectric film 29.

Then, barrier ribs 30 with a height of about 100 μm are formed in theintervals between neighboring address electrodes 28 on the surface ofthe dielectric film 29 using the same kind of lead glass substance aswas used for the dielectric film 29. The barrier ribs 30 can be formed,for example, by repeatedly applying a paste including the lead glasssubstance by using screen painting, and then firing the result.

Once the barrier ribs 30 have been formed, phosphor inks including eachof red, green and blue phosphors is applied to the sides of the barrierribs 30 and parts of the surface of the dielectric film 29 exposedbetween the barrier ribs 30, and then dried and fired to form phosphorlayers 31, 32, and 33.

An example of the phosphors typically used in a PDP is as follows.

Red phosphor: (Y_(x)Gd_(l−x)) BO₃: Eu³⁺

Green phosphor: Zn₂SiO₄: Mn

Blue phosphor: BaMgAl₁₀O₁₇: Eu³+ (or BaMgAl₁₄O₂₃: Eu³⁺)

This completes the manufacture of the back plate 26.

Here, the front and back glass substrates 21 and 27 are described asbeing made of soda lime glass, but this is just one example of asubstance that may be used, and other substances, such as glass with ahigh distortion point, may be used. Furthermore, the dielectric layer 24and the protective layer 25 need not be made of the above-mentionedsubstances, and may be replaced by appropriate substitutes. Similarly,substances for the plurality of display electrodes 22 and 23 may beselected so that, for example, transparent electrode parts 221 and 231have a satisfactory transparency. Selection of each substance may beperformed in a similar way in each embodiment, in so far as it ispossible to do so.

iii. Completion of the PDP

The manufactured front plate 20 and back plate 26 are aligned using thealignment marks 212, and fixed together with sealing glass. Then, theinside of discharge spaces 38 is degassed to form a high vacuum of8×10⁻⁷ Torr. The PDP is completed by filling the discharge spaces 38with a discharge gas formed from a mixture of Ne—Xe (neon and xenon: thelatter being 5% of the mixture) at a certain pressure (here, 2000 Torr).The discharge gas may also be a mixture of He—Xe (helium and xenon) orof He—Ne—Xe (helium, neon, and xenon).

In a manufacturing method such as the one described in the firstembodiment, a laser ablation process is performed by applying laserbeams having two different laser spots in parallel when manufacturingthe transparent electrode parts 221 and 231. A characteristic of thismethod is that the transparent electrodes 221 and 231 can bemanufactured quickly. Therefore, the method disclosed in the firstembodiment should enable the PDP to be manufactured extremelyefficiently.

Furthermore, the method disclosed in the first embodiment uses fewerprocesses that employ photolithography than is the case in aconventional manufacturing method. Consequently, problems accompanyingthe generation of exhaust gas, waste solution and the like are reduced,and so this method is extremely effective as an anti-pollution measure.

The first embodiment discloses an example of a laser ablation process inwhich other parts of the transparent conductive film 50, apart from thetransparent electrode parts 221 and 231, remain unvaporized (here, theremaining parts 211). Here, unnecessary laser ablation processing isomitted by leaving parts of the transparent conductive film 50 that donot need to be actively vaporized to form the plurality of displayelectrodes 22 and 23 and the like untouched. As a result, the laserablation processing sequence can be simplified and made faster, andmanufacturing yield improved.

Furthermore, if alignment marks are also formed on the back plate 26,and aligned with the alignment marks 212 when the process described in‘iii. Completion of the PDP’ is performed, even more precise alignmentis likely to be achieved.

In the PDP manufacturing method of the present invention, eachembodiment is characterized by a method used to manufacture theplurality of pairs of display electrodes 22 and 23, and other parts ofthe manufacturing process are, in the main, shared by both theembodiments. Therefore, the PDP manufacturing method described in thefollowing embodiment concentrates mainly on the description of themanufacturing method for the plurality of pairs of display electrodes 22and 23, and omits explanation of processes identical to those in thefirst embodiment.

Second Embodiment

When the metal electrode parts 222 and 232 of the plurality of pairs ofdisplay electrodes 22 and 23 are formed using a silver material, asecond embodiment discloses an example in which a laser ablation processis used for the formation and the annealing of the metal electrode parts222 and 232.

A silver material (here a composite of silver and powdered glass) iswidely used for the metal electrode parts 222 and 232, in place of aCr—Cu—Cr material. However, when such a silver material is coated overthe top of the transparent conductive film 50 (transparent electrodeparts 221 and 231) certain properties possessed by the silver materialcause it to be distorted into a shape having a plurality of pits andprotrusions. As a result, when the dielectric layer 24 is formed overthe entire surface of the front glass substrate 21, air bubbles aretrapped between the metal electrode parts 222 and 232 and the dielectriclayer 24, thereby causing an electrical breakdown that prevents the PDPfrom being driven properly.

A Consequently, when manufacturing the metal electrode parts 222 and 232from the silver material, it is desirable to perform the followingprocess. The metal conductive film 60 (or the metal electrode parts 222and 232) covering the transparent conductive film 50 (or the transparentelectrode parts 221 and 231) is heated, thereby melting the glasscomponent of the metal conductive film 60 (or the metal electrode parts222 and 232), and making the metal conductive film 60 (or the metalelectrode parts 222 and 232) form a smooth shape. This is referred to asannealing.

In response to the previously mentioned problem, once the metalelectrode parts 222 and 232 have been formed by the first laser beamfrom the first laser head 1030, the second embodiment performs annealingon the metal electrode parts 222 and 232 using the second laser beamfrom the second laser head 1040. The actual procedure performed is asfollows.

FIGS. 7A to 7C are partial cross-sections of the front glass substrate21, showing the manufacturing process performed on the plurality ofpairs of display electrodes 22 and 23 in the second embodiment. Notethat the shape of the pairs of display electrodes 22 and 23 is identicalto that described in the first embodiment.

First, the transparent electrode parts 221 and 231 are formed in auniform shape on the surface of the front glass substrate 21, using ascreen printing method or similar. Here, a material that is ablated at ahigher temperature than the silver material, in other words a materialthat will not be vaporized when laser ablation is performed on the metalelectrode film 60 formed from the silver material, is used to form thetransparent electrode parts 221 and 231. One actual example of such amaterial used for the transparent electrode parts 221 and 231 is tinoxide (SnO₂).

Next, the silver material is applied to the surface of the front glasssubstrate 21 on which the transparent electrode parts 221 and 231 havebeen formed, using a method such as screen printing, and then fired toform the metal conductive film 60 (thickness about 0.1 μm). FIG. 7Ashows an example in which the metal conductive film 60 has been formedover the entire surface of the front glass substrate 21, but the metalconductive film 60 may be formed over a more limited area, so that thesilver material may, for example, cover only the top of the transparentelectrode parts 221 and 231.

Next, the laser processing device 100 is used to perform settings forlaser ablation. Here, the first laser beam from the first laser head1030 is used to form the metal electrode parts 222 and 232. By combiningthe aperture (not shown) fitted to the first laser head 1030 with theobjective lens unit 1050, the first laser head 1030 may be set so as toform laser spots on the surface of the front glass substrate 21 fixed tothe table 103, each for example, being 520 μm in the y direction(approximately equal to the gap 36 between one pair of displayelectrodes 22 and 23, and 360 μm in the x direction. Then, the strengthof the first laser beam is adjusted to a level that will not adverselyaffect the transparent electrode parts 221 and 231 that are locatedbeneath the metal conductive film 60 (in other words, a level that willnot ablate the transparent electrode parts 221 and 231), but ofsufficient strength that laser ablation for the metal conductive film 60can be performed satisfactorily.

Next, the strength of the second laser beam is set. Here, since thesecond laser beam is used to anneal the metal electrode parts 222 and232, the strength of the second laser beam is set at a level sufficientto melt the glass component of the metal electrode parts 222 and 232,but not high enough to be absorbed by the transparent electrode parts221 and 231 (i.e. at a visible light wavelength near to ultravioletlight).

Furthermore, the fixed positions of the first and second laser heads1030 and 1040 of the laser torch 102 are adjusted, setting the size ofthe laser spots, and the position of the laser spots relative to themetal conductive film 60 covering the front glass substrate 21.

Note that here the laser processing device 100 is described as being setso that the first and second laser heads 1030 and 1040 are driven inparallel, but the invention need not be limited to this laser ablationprocess. Instead, for example, the laser ablation performed by thesecond laser head 1040 may be started once the laser ablation performedby the first laser head 1030 has been completely finished.

Once setting of the alignment of the first and second laser heads 1030and 1040, and of the strength of each laser beam has been completed,laser ablation process starts, so that parts of the metal conductivefilm 60, apart from the metal electrode parts 222 and 232 and theelectrode extensions (not shown), are vaporized. As a result, metalelectrode parts 222 and 232 with a width of about 50 μm, as shown inFIG. 7B, are formed.

However, at this point, the shape of the metal electrode parts 222 and232 is distorted into a shape with a large number of pits andprotrusions, as shown in the cross-section of the front glass substrate21 in FIG. 8A. This phenomenon is caused by certain properties of thesilver material, but if it is left unaltered, a large number of airbubbles will be trapped when the dielectric layer 24 is formed, aspreviously described, and the performance of the PDP will be reduced.

Here, as a characteristic of the second embodiment, the second laserbeam from the second laser head 1040 is used to anneal the metalelectrode parts 222 and 232 that have been formed by the first laserhead 1030 as shown in FIG. 8A (FIG. 7C). This melts the glass componentsof the metal electrode parts 222 and 232, thereby making the surface ofthe metal electrode parts 222 and 232 smooth, as shown in FIG. 8B. Ifthis embodiment is used, the metal electrode parts 222 and 232 can bequickly manufactured using the laser ablation process. In addition,performing the processes for forming and annealing the metal electrodeparts 222 and 232 in parallel, enables high-quality PDPs to bemanufactured at a high yield, even if a substance that is prone togenerate pits and protrusions, such as a silver material, is used toform the metal conductive film 60.

To give more precise details, the presence of as many as 24 air bubblesof about 10 μm in diameter has been verified in the dielectric layer 24of a conventionally manufactured XGA PDP, but in a PDP manufacturedusing the method disclosed in the present embodiments that figure isreduced to about one. As a result, the resistance of the PDP toelectrical breakdown is increased from the conventional level of about800V to about 2 kV.

Note that the laser strength may be such that as to have a wavelengthequivalent to that of visible light, as one idea for ensuring that thefirst laser beam from the first laser head 1030 only ablates the metalconductive film 60.

Furthermore, as a variation of the second embodiment, the transparentelectrode parts 221 and 231 may be formed by a separate laser ablationstep, prior to forming the metal electrode parts 222 and 232 using laserablation. In this case, alignment marks 212 are formed by processing thetransparent electrode parts 221 and 231 as described in the firstembodiment, and then the metal electrode parts 222 and 232 can be formedin the correct positions using the alignment marks 212, and annealingperformed. Here, appropriate masking is required to prevent the metalconductive film 60 from covering the alignment marks 212.

Furthermore, in the second embodiment, an example in which the laserablation of the metal electrode parts 222 and 232 is a performed inparallel with annealing of the metal electrode parts 222 and 232 isdescribed but, alternatively, the formation and the annealing of thetransparent electrode parts 221 and 231 may be performed in parallel. Inother words, the first laser beam may perform patterning of thetransparent electrode parts 221 and 231, while the second laser beam isused to anneal the transparent electrode parts 221 and 231 (or thetransparent conductive film 50). In this case, the diameter of crystalparticles in the SnO₂ quadruples. These crystals form the transparentelectrode parts 221 and 231 (or the transparent conductive film 50), andsuch an increase in size improves their ability to bond with the metalelectrode parts 222 and 232 (or the metal conductive film 60).

In actual fact, this annealing enables the proportion of withstandvoltage defects occurring during manufacture of the transparentelectrode parts 221 and 231 that can be repaired to be improved from theconventional level of about 80% to about 96%.

Here, the strength of the second laser beam should be about 30% strongerthan that used for annealing the metal electrodes 222 and 232, due tothe transparency of the transparent electrode parts 221 and 231.

Other Variations of the Embodiments

The following describes a number of other applications of the inventionnot described in the first and second embodiments.

First Variation

FIG. 9 is a frontal view of the front glass substrate 21, showing asituation in which the transparent electrodes are being manufacturedaccording to a variation of the PDP manufacturing method describedherein. As shown in the drawing, in this first variation, thetransparent electrode parts 221 and 231 are formed using the laserablation process and line resistance values of each of the transparentelectrode parts 221 and 231 are measured. Then, arbitrary transparentelectrode parts 221 and 231 are refined based on the corresponding lineresistance values, and the line resistance values corrected.

To be more precise, the transparent conductive film 50 covering thesurface of the front glass substrate 21 is processed using laserablation to form the transparent electrode parts 221 and 231 (in FIG. 9the shape of the transparent electrode parts 221 and 231 is depictedusing straight lines to made it easier to understand). Here, the gap 36between a pair of display electrodes 22 and 23, and the gap 37 betweenpairs of neighboring display electrodes 22 and 23 are formed using onlythe first laser beam, with the gap 37 between pairs of neighboringdisplay electrodes 22 and 23 formed by scanning the first laser beam inthe x direction for several successive strokes.

Next, probes 301 a and 301 b are brought into contact with the ends ofeach of the transparent electrode parts 221 and 231 in the x direction,and the line resistance of the transparent electrode parts 221 and 231measured using a widely known line resistance measuring device (notshown) that has been connected to the probes 301 a and 301 b. The probes301 a and 301 b are fixed to the sides of the laser torch guide 101, andthe line resistance measuring device has already been connected to acontrol unit (for example an input terminal such as a personal computer)of the laser processing device 100. In addition, a reference value forcomparison is stored in a memory of the input terminal (not shown), andthe input terminal successively compares line resistance values of thetransparent electrodes 221 and 231 obtained from the line resistancemeasuring device with the reference value. Then, in order to correcterrors in the line resistance value of certain transparent electrodes221 and 231 calculated as a result of the comparison, a second laserbeam strength appropriate for the degree of error involved is set in theinput terminal, and the second laser beam applied to the correspondingtransparent electrode parts 221 and 231.

As a result, the transparent electrode parts 221 and 231 to which thelaser is applied are refined, thereby correcting the line resistancevalue, and a PDP having uniform display characteristics when driven canbe manufactured.

In other words, in this first variation, the processes for (1) formingthe transparent electrode parts 221 and 231 using the first laser beam,(2) measuring line resistance values of the transparent electrode parts221 and 231, and (3) correcting the line resistance values of thetransparent electrode parts 221 and 231 using the second laser beam,based on the measured resistance values, can be performed in parallel.

To give a specific example, an average line resistance value of thetransparent electrodes 221 and 231 after formation is conventionallyabout 1.0 kΩ, and a degree of variation σ is about 17%. The correctionof line resistance values performed in this first variation, however,produces an average line resistance value of 0.5 kΩ, and the degree ofvariation σ is improved to about 7%.

Second Variation

FIG. 10 is a frontal view of the front glass substrate 21 showing asituation in which the transparent electrode parts 221 and 231 are beingmanufactured according to a variation of the PDP manufacturing methoddescribed herein. In the first variation, an example in whichtransparent electrode parts 221 and 231 are formed and then the lineresistance value of the formed transparent electrode parts 221 and 231measured is described. This second variation, however, is characterizedby a process in which a detailed structure of the formed transparentelectrode parts 221 and 231 is examined using a CCD (charge coupleddevice) camera, and problem areas repaired.

To be more precise, once transparent electrode parts 221 and 231 havebeen formed, they are photographed using a CCD camera 70 fixed to theside of the laser torch guide 101. Next, the pictures of the transparentelectrode parts 221 and 231 obtained by the CCD camera 70 are input intoan input terminal, such as a personal computer, connected to the controlunit of the laser processing device 100, and a well known PM (patternmatching) process is performed. Then, parts of the shape of thetransparent electrode parts 221 and 231 in which problems have beendetected by the PM process (for example, undesirable small pits andprotrusions) are repaired by applying the second laser beam.

If this second variation is applied, the time required to perform thePDP manufacturing process, as well as the number of process stepsrequired, can be reduced, and variations in shape restricted, enabling aPDP having transparent electrode parts 221 and 231 of a uniform qualityto be manufactured.

Third Variation

FIG. 11 is a frontal view of the front glass substrate 21 showing asituation in which the transparent electrode parts 221 and 231 and thelike are formed according to a third variation of the PDP manufacturingmethod, described herein. This third variation, like the firstvariation, measures line resistance values for transparent electrodeparts 221 and 231, and refines certain transparent electrode parts 221and 231 based on corresponding measured line resistance values, therebycorrecting the line resistance value. However, the third variation ischaracterized by adding a process, in which a mask 300 is applied topart of the front glass substrate 21, to this processing sequence.

In other words, when the transparent conductive film 50 is formed on thefront glass substrate 21 using sputtering or a similar method, themethod in the third variation involves arranging the mask 300, prior toperforming sputtering, so as to cover areas of the front glass substrate21 from which the transparent conductive film 50 would have to beeliminated were it to be applied. This enables the application area ofthe transparent conductive film 50 to be reduced efficiently. As aresult, the laser ablation process can be simplified, thus shorteningthe amount of time required for the process, and improving yield.

Note that remaining parts 250 form part of the transparent conductivefilm 50 since these remaining parts 250 are used to form the alignmentmarks 212, but if there is no need to form the alignment marks 212, themask 300 can also be applied to these remaining parts 250.

A device similar to the mask 300 may also be used in the first andsecond embodiments, and in the first and second variations.

In addition, as a further variation, the transparent electrode parts 221and 231 or the metal electrode parts 222 and 232 may be formed byapplying the first laser beam, and then the second laser beam applied tothe transparent electrode parts 221 and 231 or the metal electrode parts222 and 232. The reflected second laser beam is captured by a well-knownlaser microscope, and the shape of the transparent electrode parts 221and 321 or the metal electrode parts 222 and 232 examined.

Cross-section of Transparent Electrode Parts Formed by Laser Ablation

FIG. 12A is a cross-section of the front glass substrate 21 along the zdirection, showing, as one example, the shape of the transparentelectrodes 221 and 231 manufactured based on the first variation of thePDP manufacturing method.

In other words, the transparent electrodes 221 and 231 shown in FIG. 12Aare shaped so as to curve upward higher at edges 80 a and 80 b than atthe center. The edges 80 a and 80 b are processed so that portionshaving an acute angle are smoothed into a rounded shape. Research hasshown that this kind of shape can be achieved if ITO is used for thetransparent conductive material.

Here, the concept denoted by the term ‘rounded shape’ does not onlyinclude perfect spheres, but also any shape which has an obtuse angle(i.e. an angle of more than 90°), rather than an acute angle (an angleof 90° or less).

Next, as shown in FIG. 12B, edges 81 a and 81 b curve upward in the zdirection (in other words toward the back plate 26), and have a smoothshape with no acute angles. Research has shown that this kind of shapecan be achieved if SnO₂ is used for the transparent conductive material.

In FIG. 12C, edges 82 a and 82 b protrude vertically upward in the zdirection (toward the back plate 26) from the xy plane formed by thefront glass substrate 21, the upper portion of each edge 82 a and 82 bbeing rounded, and having a smooth shape with no acute angles. The shapeof edges 82 a and 82 b shown in FIG. 12C can be obtained by furtherprocessing the shape shown in either FIG. 12A or 12B. The processing forthese shapes is described later in this specification.

If the transparent electrode parts 221 and 231 are formed with edges 80a to 82 a and 80 b to 82 b shown in any one of FIGS. 12A to 12C, thefollowing effects can be obtained.

Conventionally, since an electric field for surface discharge tends toconcentrate in the angled parts of the plurality of pairs of displayelectrodes 22 and 23 bordering the discharge spaces 38, the electricfield is concentrated at areas near to the angled parts of the pairs ofdisplay electrodes 22 and 23, making it more likely that abnormaldischarge will be generated.

In contrast, if the transparent electrode parts 221 and 231 are providedwith one of edges 80 a to 82 a and 82 a to 82 c or similar, the angledparts of the pairs of display electrodes 22 and 23 bordering thedischarge spaces 38 no longer exist. Consequently, the phenomenon inwhich the electric field generated in the discharge spaces 38 isconcentrated in parts nearer to the angled parts is reduced. Therefore,generation of abnormal discharge and electrical breakdowns in thedielectric layer 24 can be avoided.

Furthermore, edges 80 a to 82 a, and 80 b to 82 b protrude upward higherthan the central parts of the transparent electrode parts 221 and 231(in other words, the part of the dielectric layer 24 covering the edges80 a to 80 c, and 81 a to 81 c is thinner), thereby enabling the voltageat both the discharge start time and the sustain discharge time of thesurface discharge to be reduced.

To be precise, marked effects can be produced when the radius of therounded parts of the edges 80 a to 82 a, and 80 b to 82 b is about 0.05to 0.1 μm, in comparison with an average thickness of the transparentelectrode parts 221 and 231 of about 0.1 to 0.13 μm.

As explained above, transparent electrode parts 221 and 231 having theedges 80 a, 81 a, 80 b, 81 b or similar can be formed, for example, byperforming a laser ablation process on the transparent conductive film50 covering the surface of the front glass substrate 21. This means thatthe areas of the transparent conductive film 50 to which a laser beam isapplied are ablated by being heated to a high temperature, while thoseareas of the transparent conductive film 50 surrounding the ablatedareas melt due to the high temperature, and curve upward as a result ofsurface tension. Therefore, appropriate adjustment of the strength ofthe laser beam (i.e setting at a strength slightly more than thatrequired to ablate the transparent conductive film 50) enables thislaser ablation process to be performed.

Here, the edges 82 a and 82 b shown in FIG. 12C can be formed using themethod shown in FIG. 13. FIG. 13 shows an example of a method in whichthe edges 82 a and 82 b have been formed based on the edges 82 a and 82b.

In this method, a photoresist 70 is applied to the surface of the frontglass substrate 21 on which transparent electrode parts 221 and 231having the edges 80 a and 80 b have been formed using laser ablation(FIG. 13A).

Next, a mask 80, having a certain pattern (here, a pattern that masksall of the surface apart from the gaps between the electrodes in eachpair, and between pairs of neighboring electrodes) is fixed to thesurface of the front glass substrate 21. Once the photoresist 70 hasbeen developed, an alkaline solution is used to dispose of those partsof the photoresist 70 that were not masked (FIG. 13B).

Following this, the parts of the photoresist 70 which were not disposedof using the alkaline solution are washed off, thereby eliminating allof the photoresist 70 from the surface of the front glass substrate 21(FIG. 13C).

In this way, transparent electrode parts 221 and 231 having the edges 82a and 82 b shown in FIG. 12C are formed. This process is particularlyeffective when the transparent electrode parts 221 and 231 are formed ina precise shape (in other words cells are small) since it enables theedges of 82 a and 82 b to be formed cleanly.

Note, other edges apart from the edges 80 a to 82 a, and 80 b to 82 bmay be manufactured using a laser process that combines first and secondlaser beams of different strengths (for example, the second laser beammay be slightly weaker than the first laser beam). Here, for example,basic manufacturing of each transparent electrode part 221 and 231 maybe performed by the first laser beam, and then the second laser beamapplied to parts of the transparent electrode parts 221 and 231, tocomplete their formation.

In addition, the edges 80 a to 82 a, and 80 b to 82 b, or similar neednot be provided along both sides of the transparent electrode parts 221and 231. Instead, it is sufficient for the edges 80 a to 82 a to beprovided only along the sides of the pair of display electrodes 22 and23 neighboring the gap 36.

Other Considerations

The embodiments describe an example using a YAG laser with a wavelengthof 1.06 μm. However, another type of laser such as an excimer laser or agas laser may be used. In addition, the wavelength of the laser need notbe limited to 1.06 μm, and the laser may be set at other appropriatewavelengths, such as 0.53 μm, and 0.25 μm.

Furthermore, the part of the first embodiment describing the formationof the transparent electrode parts 221 and 231, discloses an example inwhich CVD or a similar method is used as a manufacturing method for thetransparent conductive film 50, but another method such as sputtering orscreen printing may be used as appropriate. The same applies to themethod used to form the metal electrode parts 222 and 232.

In addition, instead of a SnO₂—SbO₃ material, the material used for thetransparent conductive film 50 may be a SnO₂—F material, an InGaZnO₄material, a Cd₂SnO₄ material, an In₂O₃—SnO₃ material, a GaInO₃ material,a ZnO—GeO material, or any other well known transparent material.

Furthermore, a silver material and a Cr—Cu—Cr material or similar aredescribed as examples of materials used to formed the metal electrodeparts 222 and 232, but other metal conductive materials may also beused. However, the effects obtained in the second embodiment arebelieved to be particularly marked when a silver material is used forthe metal electrode parts 222 and 232.

Furthermore, pairs of display electrodes 22 and 23 are described in theembodiments and variations as being formed from the transparentelectrode parts 221 and 231, and the metal electrode parts 222 and 232.However, the metal conductive film 60 may be formed directly over theentire surface of the front glass substrate 21 using sputtering, andthen laser processed to form the metal electrode parts 222 and 232. Inthis case, each pair of display electrodes 22 and 23 is constructed fromonly the metal electrode parts 222 and 232 (in other words the displayelectrodes 22 and 23 do not have the transparent electrode parts 221 and231).

In addition, the first embodiment gives an example in which thetransparent conductive film 50 is formed on the front glass substrate21, and then the transparent electrode parts 221 and 231 are formed,followed by the metal electrode parts 222 and 232. However, thetransparent conductive film 50 and the metal conductive film 60 may besuccessively formed on the front glass substrate 21, and the metalelectrode parts 222 and 232 formed by photolithography or similar,before the transparent electrode parts 221 and 231 are formed usinglaser ablation.

Furthermore, the embodiments describe examples in which a plurality ofpairs of display electrodes 22 and 23 having protrusions are formed, andthe variations of the embodiments an example in which a plurality ofpairs of display electrodes 22 and 23 are formed using straight lines.However, the protrusions may be formed by performing laser ablation onthe transparent electrode parts 221 and 231 by, for example, performinga pulse laser scan so that a plurality of elliptic laser spots areformed with parts of each laser spot overlapping slightly lengthwise.Furthermore, the shape of the display electrodes 22 and 23 need not belimited to one that has a protrusion, and may be changed to a shape thatmatches the appropriate cell size or similar. The shape of the laserhead apertures should be changed to effect such a change in the shape ofthe plurality of pairs of display electrodes 22 and 23.

Here, if the shape of the laser spots is changed by changing the shapeof the apertures 1031 and 1041 used in the embodiments, so that arectangular laser spot is obtained, a wide variety of laser ablationprocessing can be performed by connecting a plurality of laser spots inthe x and y directions.

Furthermore, an example in which cross-shaped reverse alignment marks212 are formed along the length of the front glass substrate at the topand bottom during laser ablation of the transparent conductive film 50is disclosed. However, the shape and position of these alignment marks212 need not of course be limited to that explained, and appropriatechanges may be made. In addition, the alignment marks 212 may be usedeither for alignment of the front glass substrate 21 with the back glasssubstrate 27, or for alignment of the transparent electrode parts 221and 231 with the metal electrode parts 222 and 232.

Furthermore, an example in which the transparent conductive film isformed over the entire surface of the front glass substrate 21, and thenprocessed using a laser to form the transparent electrode parts 221 and231 is explained. Alternatively, areas such as the electrode extensionforming areas that do not need to be covered by the transparentconductive film 50 may be masked, and the transparent conductive film 50then formed using a method such as sputtering.

In addition, the embodiments concentrate on an example in which thetransparent electrode parts 221 and 231 are formed using a laserablation process, and the metal electrode parts 222 and 232 are formedusing photolithography, and an example in which the transparentelectrode parts 221 and 231 are formed using screen printing, and themetal electrode parts 222 and 232 are formed using a laser ablationprocess. However, the invention need not be limited to suchmanufacturing methods, provided that at least either the transparentelectrode parts 221 and 231, or the metal electrode parts 222 and 232,are formed using laser ablation. Should the plurality of pairs ofdisplay electrodes 22 and 23 be formed from only the metal electrodeparts 222 and 232, however, laser ablation must be performed.

The embodiments describe an example in which the laser torch 102 isprovided with the first laser head 1030 and the second laser head 1040,and the first and second laser heads 1030 and 1040 perform simultaneousor successive laser ablation. However, the order in which the laserablation is performed may be changed appropriately, insofar as it ispossible (for example the process for manufacturing a-gap between a pairof display electrodes, and the process for manufacturing a gap betweenpairs of neighboring display electrodes may be interchanged).

The embodiments give specific examples such as the numerical valuesrelating to the laser ablation process (laser spot size and amounts ofmovement in the x and y directions), but of course the invention neednot be limited to such figures, and these may be changed as appropriate,in accordance, for example, with the size of the PDP that is to bemanufactured.

Furthermore, when performing the laser ablation process, neighboringlaser spots may overlap by a certain amount. This allows a single strokein the laser ablation process to be performed without pause. However, insuch a case the aperture and the shape of the laser spots need to be setwith reference to the size of the overlapping laser spot portions.

The embodiments disclose an example in which two laser heads 1030 and1040 perform laser ablation in parallel. However, the number of laserheads for emitting laser beams may be one, or three or more. If only onelaser head is used, a plurality of apertures should be usedinterchangeably as appropriate. If a plurality of laser heads are used,these may be set to emit a plurality of laser beams each havingdifferent characteristics, such as laser spot shape, laser spot size,and laser strength. This enables formation of the plurality of pairs ofdisplay electrodes 22 and 23, and various repairs such as correction ofline resistance, and fine shape adjustments to be made to the displayelectrodes 22 and 23 to be performed more speedily, and thus isdesirable.

Industrial Applicability

The PDP manufacturing method of the invention enables at least someparts of the manufacturing process, such as photolithography, usedconventionally to manufacture a plurality of pairs of display electrodes22 and 23, to be replaced by a laser ablation process. Laser ablationrequires fewer steps than photolithography, and these steps can beperformed in a short time. As a result, the PDP manufacturing processcan obtain a more satisfactory product yield, and contribute to areduction in product costs.

Furthermore, the laser ablation process generates much less exhaust gasand waste solution than photolithography. Therefore, generation of usedphotoresist and waste solution from etching or similar is restricted,making the method an effective anti-pollution measure.

The PDP in the present invention is provided with alignment marks on thefront glass substrate for alignment of the plates, and of thetransparent and metal electrode parts. This ensures that the front andback glass substrates, and the transparent and metal electrodes areprecisely aligned, making full use of the fundamental designcharacteristics of the PDP.

What is claimed is:
 1. A surface discharge AC plasma display panelmanufacturing method comprising a display electrode forming step offorming a plurality of pairs of display electrodes in parallel lines ona main surface of a first plate, and a plate sealing step of aligningthe main surface of the first plate with a main surface of a secondplate, and sealing the first and second plates together, and in thedisplay electrode forming step, (1) the plurality of pairs of displayelectrodes are formed by (a) coating the main surface of the first platewith a transparent conductive film, and vaporizing parts of thetransparent conductive film using laser ablation to form transparentelectrode parts from remaining parts of the transparent conductive film,and (b) coating at least surfaces of the transparent electrode partswith the metal electrode material to form metal electrode parts that arein electrical contact with the transparent electrode parts, and (2) adielectric layer is formed so as to embed the transparent electrodeparts and the metal electrode parts.
 2. The surface discharge AC plasmadisplay panel manufacturing method of claim 1, wherein in the displayelectrode forming step, the plurality of pairs of display electrodes areformed by (1) performing laser ablation to vaporize parts of thetransparent conductive film to form transparent electrode parts andalignment marks, and (2) coating at least surfaces of the transparentelectrode parts with metal electrode material to form metal electrodeparts, the alignment marks being used to align the metal electrodematerial with the transparent electrode parts.
 3. The surface dischargeAC plasma display panel manufacturing method of claim 1, wherein in thedisplay electrode forming step, the main surface of the first plate iscoated with the transparent conductive film, and laser ablation isperformed so as to avoid processing transparent conductive film coatingone or more outer areas of the main surface.
 4. A surface discharge ACplasma display panel manufacturing method comprising a display electrodeforming step of forming a plurality of pairs of display electrodes inparallel lines on a main-surface of a first plate, and a plate sealingstep of aligning the main surface of the first plate with a main surfaceof a second plate, and sealing the first and second plates together,wherein in the display electrode forming step, (1) the plurality ofpairs of display electrodes are formed by (a) coating the main surfaceof the first plate with transparent conductive film, (b) coating metalelectrode material over the transparent conductive film to form metalelectrode parts, and (c) performing laser ablation to vaporize parts ofthe transparent conductive film to form transparent electrode parts thatare remaining parts of the transparent conductive film, and (2) adielectric layer is formed so as to embed the transparent electrodeparts and the metal electrode parts.
 5. The surface discharge AC plasmadisplay panel manufacturing method of claim 4, wherein in the displayelectrode forming step, the plurality of pairs of display electrodes areformed by (1) successively coating the main surface of the first platewith the transparent conductive film and the metal electrode material,and (2) successively performing laser ablation to vaporize parts of thetransparent conductive film and the metal electrode material to form thetransparent and metal electrode parts.
 6. A surface discharge AC plasmadisplay panel manufacturing method comprising a display electrodeforming step of forming a plurality of pairs of display electrodes inparallel lines on a main surface of a first plate, and a plate sealingstep of aligning the main surface of the first plate with a main surfaceof a second plate, and sealing the first and second plates together,wherein in the display electrode forming step, a metal material is usedas the display electrode material and the plurality of pairs of displayelectrodes are formed by (1) coating the main surface of the first platewith the metal material, and (2) performing laser ablation to parts ofthe metal material, remaining parts of the metal material forming thedisplay electrodes.
 7. A surface discharge AC plasma display panelmanufacturing method comprising a display electrode forming step offorming a plurality of pairs of display electrodes in parallel lines ona main surface of a first plate, and a plate sealing step of aligningthe main surface of the first plate with a main surface of a secondplate, and sealing the first and second plates together, wherein in thedisplay electrode forming step, the plurality of pairs of displayelectrodes and alignment marks are formed together on the main surfaceof the first plate by performing laser ablation to vaporize parts of thedisplay electrode material, remaining parts of the display electrodematerial forming the display electrodes, and in the plate sealing step,the first and second plates are sealed together by using the alignmentmarks to align the main surface of the first plate with the main surfaceof the second plate.
 8. The surface discharge AC plasma display panelmanufacturing method of claim 7, wherein in the display electrodeforming step, reverse alignment marks are formed by performing laserablation to vaporize parts of the display electrode material coating themain surface of the first plate.
 9. The surface discharge AC plasmadisplay panel manufacturing method of claim 8, wherein in the displayelectrode forming step, the reverse alignment marks are each formed in across shape.
 10. A surface discharge AC plasma display panelmanufacturing method comprising a display electrode forming step offorming a plurality of pairs of display electrodes in parallel lines ona main surface of a first plate, and a plate sealing step of aligningthe main surface of the first plate with a main surface of a secondplate, and sealing the first and second plates together, wherein: in thedisplay electrode forming step, the plurality of pairs of displayelectrodes, alignment marks and a plurality of electrode extensionforming areas are formed by (1) coating the main surface of the firstplate with display electrode material, and (2) performing laser ablationto vaporize parts of the display electrode material, the plurality ofelectrode extension areas being formed near either end of the pluralityof pairs of display electrodes, and in the plate sealing step, the firstand second plates are sealed together using the alignment marks to alignthe main surface of the first plate with the main surface of the secondplate.
 11. A surface discharge AC plasma display panel manufacturingmethod comprising a display electrode forming step of forming aplurality of pairs of display electrodes in parallel lines on a mainsurface of a first plate, and a plate sealing step of aligning the mainsurface of the first plate with a main surface of a second plate, andsealing the first and second plates together, wherein in the displayelectrode forming step, the plurality of pairs of display electrodes areformed by (1) coating one or more areas on the main surface of the firstplate with the display electrode material, the one or-more areas beingsmaller than a total area of the main surface, and at least as long asthe display electrodes, and (2) performing laser ablation to vaporizeparts of the display electrode material, remaining parts of the displayelectrode material forming the display electrodes.
 12. The surfacedischarge AC plasma display panel manufacturing method of claim 11,wherein in the display electrode forming step, the plurality of pairs ofdisplay electrodes are formed by (1) masking one or more areas of themain surface of the first plate that are not used to form the pluralityof pairs of display electrodes, (2) substantially coating the displayelectrode material on one or more areas of the main surface that is usedto form the plurality of pairs of display electrodes, and (3) performinglaser ablation to vaporize parts of the display electrode material. 13.The surface discharge AC plasma display panel manufacturing method ofclaim 12, wherein in the display electrode forming step, the pluralityof pairs of display electrodes and the alignment marks are formed by (1)masking one or more areas of the main surface of the first plate thatare not used to form the plurality of pairs of display electrodes andthe alignment marks, (2) substantially coating areas of the main surfacethat are used to form the plurality of pairs of display electrodes andthe alignment marks with the display electrode material, and (3)performing laser ablation to vaporize parts of the display electrodematerial.
 14. A surface discharge AC plasma display panel manufacturingmethod comprising a display electrode forming step of forming aplurality of pairs of display electrodes in parallel lines on a mainsurface of a first plate, and a plate sealing step for aligning the mainsurface of the first plate with a main surface of a second plate onwhich a plurality of address electrodes have been arranged in parallellines, so that the plurality of pairs of display electrodes intersectwith the address electrodes, and sealing the first and second platestogether, the plurality of pairs of display electrodes being formed inthe display electrode forming step by (1) coating the main surface ofthe first plate with display electrode material, and (2) performinglaser ablation to vaporize parts of the display electrode material byapplying a first laser beam and a second laser beam in parallel to thedisplay electrode material, the remaining parts of the display electrodematerial forming the display electrodes.
 15. The surface discharge ACplasma display panel manufacturing method of claim 14, wherein in thedisplay electrode forming step, the plurality of pairs of displayelectrodes are formed by (1) coating the main surface of the first platewith the display electrode material, and (2) applying a laser beamhaving a first spot shape and a laser beam having a second spot shapedifferent from the first spot shape to the display electrode material.16. The surface discharge AC plasma display panel of claim 15, whereinin the display electrode forming step, the main surface of the firstplate is coated with the display electrode material, and the pluralityof pairs of display electrodes are formed so that each area at which apair of display electrodes intersect with an address electrode has adisplay electrode pattern of a same size and shape.
 17. The surfacedischarge AC plasma display panel of claim 15, wherein in the displayelectrode forming step, the laser beam having the first laser spot shapeand the laser beam having the second laser spot shape are differentlysized rectangles whose width is orthogonal to a laser beam scanningdirection.
 18. The surface discharge AC plasma display panelmanufacturing method of claim 14, wherein in the display electrodeforming step, gaps between a pair of display electrodes are formed byapplying the laser beam having the first laser spot shape to the displayelectrode material, and gaps between neighboring pairs of displayelectrodes are formed by applying the laser beam having the second laserspot shape to the display electrode material.
 19. A surface discharge ACplasma display panel manufacturing method comprising a display electrodeforming step of forming a plurality of pairs of display electrodes inparallel lines on a main surface of a first plate, and a plate sealingstep of aligning the main surface of the first plate with a main surfaceof a second plate on which a plurality of address electrodes and aplurality of barrier ribs have been arranged in parallel lines andsealing the first and second plates together, wherein in the displayelectrode forming step, the display electrode material consists oftransparent conductive film and metal electrode material, and (1) aplurality of transparent electrode parts are formed on the main surfaceof the first plate, (2) the main surface of the first plate includingthe transparent electrode parts is coated with the metal electrodematerial, (3) metal electrode parts are formed by applying a first laserbeam to the metal electrode material, and (4) resistance values of themetal electrode parts are adjusted by annealing performed using a secondlaser beam.
 20. A surface discharge AC plasma display panel formed byaligning a main surface of a first plate with a main surface of a secondplate, and sealing the first and second plates together, a plurality ofpairs of display electrodes having been formed in parallel lines on themain surface of the first plate, each pair of display electrodes beingformed from a transparent electrode part and a metal electrode part thatare in electrical contact, wherein alignment marks for performingalignment of the transparent electrode parts and the metal electrodeparts are formed on the main surface of the first plate, the transparentand metal electrode parts having been formed by laser ablation.
 21. Asurface discharge AC plasma display panel formed by aligning a mainsurface of a first plate, on which a plurality of pairs of displayelectrodes having transparent electrode parts have been formed inparallel lines, with a main surface of a second plate, wherein across-section across a width of the transparent electrode parts isshaped so that an edge of each transparent electrode bordering a gapbetween a pair of display electrodes and facing the second plate isrounded by performing laser ablation.
 22. The surface discharge ACplasma display panel of claim 21, wherein the cross-section across thewidth of each of the transparent electrode parts is shaped so that anedge of each transparent electrode part bordering a gap between a pairof electrodes and facing the second plate is rounded, and curved so asto protrude upward more than the center of the transparent electrodeparts.
 23. A surface discharge AC plasma display panel formed byaligning a first plate, on which a plurality of pairs of displayelectrodes having transparent electrode parts have been formed inparallel lines, with a main surface of a second plate, wherein across-section across the width of the transparent electrode parts isshaped so that both edges of the transparent electrode parts facing thesecond plate are rounded by performing laser ablation.
 24. The surfacedischarge AC plasma display panel of claim 23, wherein the cross-sectionacross the width of the transparent electrode parts is shaped so thatboth edges of the transparent electrode parts facing the second plateare rounded, and curve upward more than the center of the transparentelectrode parts.